GCN Circulars
GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.
Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search
To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.
Advanced Search Examples (click to copy):
subject:"Swift"body:"GRB"submitter:"Judith Racusin"- GRB 140626A: Swift-BAT refined analysis
- GRB 140626A: Swift-XRT refined Analysis
- GRB 140626A: Swift/UVOT Upper Limits
- GRB 140626A: Enhanced Swift-XRT position
- GRB 140626A: GROND Afterglow Candidate
- GRB 140619B: Suzaku WAM observation of the prompt emission
- GRB 140626A: Swift detection of a burst
- Further Swift/XRT observations of GRB140620A/iPTFcva
- GRB140606B/iPTF14bfu: Keck detection of an associated supernova
- GRB 140620A / iPTF14cva: TShAO optical observations
- GRB 140624A: Fermi GBM observation of a short burst
- GRB 140623A: Swift-XRT and UVOT observations
- GRB 140623A / iPTF14cyb: Fermi GBM detection
- GRB 140621A: Swift-XRT observations
- GRB 140622A: iTelescope.Net T11 Optical Observation
- GRB 140621A: Fermi GBM detection
- GRB 140622A: Swift/UVOT Upper Limits
- Konus-Wind observation of GRB 140621A
- IPN Triangulation of GRB 140621A
- Konus-Wind observation of GRB 140619A
- Fermi 425193729 / iPTF14cyb: Discovery of optical afterglow
- GRB 140622A: KAIT Optical Upper Limit
- GRB 140620A / iPTF14cva: Konkoly optical observations
- GRB 140622A: Swift-XRT refined Analysis
- GRB 140622A: An unusual short event, Swift-BAT refined analysis
- GRB 140622A: VLT/X-shooter redshift
- GRB 140622A: RATIR Optical and NIR Observations
- GRB 140622A: GROND Upper limits
- GRB 140622A: Enhanced Swift-XRT position
- GRB 140622A: Swift detection of a short burst
- GRB 140620A: Swift/UVOT Detection
- GRB 140606B / iPTF 14bfu: SAO RAS optical observations
- Correction to GCN 16429 (GRB 140619C)
- Konus-Wind observation of GRB 140619C
- GRB 140620A: Swift-XRT observations
- IPN Triangulation of GRB 140619C (long/very intense)
- GRB 140620A / iPTF14cva: Fermi GBM observations
- Fermi 424934131 / iPTF14cva: Discovery and Redshift of Optical Afterglow
- GRB 140619B: Swift-XRT observations
- GRB 140619A: Swift-BAT refined analysis
- GRB 140610A: TShAO optical upper limit
- GRB 140619B: Fermi-LAT Detection
- GRB 140619B: Fermi GBM detection of a short GRB
- GRB 140619A: Swift/UVOT Observations
- GRB 140619A: Swift-XRT refined Analysis
- GRB 140619A: Enhanced Swift-XRT position
- GRB 140619A: Swift detection of a burst with a possible optical counterpart
- Swift trigger 601928 is V490 Cep: BAT+XRT refined analysis.
- Swift-BAT trigger 601928: Detection of a possible outburst from V490 Cep
- GRB 140606B: Swift XRT final light curve
- GRB 140606A: BTA and OSN optical observations
- GRB 140614C: 1.23m CAHA (+EDIPO) observations
- GRB 140614B: MOSFIRE Ks-band nondetection
- GRB 140614C found in ground analysis of BAT data
- GRB 140614B: MITSuME Akeno upper limits
- GRB 140614B: Swift-XRT refined Analysis
- GRB 140614B: MITSuME Okayama upper limits
- GRB 140614B: Swift-BAT refined analysis
- GRB 140606B / iPTF 14bfu: Mondy optical observations
- GRB 140614A: Swift-BAT refined analysis
- GRB 140614A: X-shooter redshift
- GRB 140614B: Swift/UVOT Upper Limits
- GRB 140614B: RATIR Optical and NIR Observations
- GRB 140606B / iPTF 14bfu: AAO optical observations
- GRB 140614A: Swift/UVOT Upper Limits
- GRB 140614A: Swift-XRT refined Analysis
- GRB 140614B: Enhanced Swift-XRT position
- GRB 140614B: Swift detection of a burst
- GRB 140614A: Enhanced Swift-XRT position
- GRB 140614A: GROND afterglow candidate
- GRB 140614A: Swift detection of a burst
- GRB 140611A: Swift-XRT observations
- Konus-Wind observation of GRB 140611A
- GRB 140610A: Swift-XRT refined Analysis
- GRB 140606B / iPTF 14bfu: MOSFIRE NIR imaging
- GRB 140611A Detection of a source in BAT ground analysis
- GRB 140610A: Fermi GBM Detection
- IPN Triangulation of GRB 140611A (short/hard)
- GRB 140610A: RATIR Optical and NIR Observations
- GRB 140610A: Swift-BAT refined analysis
- GRB 140610A: MASTER optical observations
- GRB 140610A: Swift/UVOT Upper Limits
- Konus-Wind observation of GRB 140610A
- Swift/XRT returns to normal observing
- GRB140606B: DCT time of observation correction
- GRB 140610A: Swift-XRT observations
- GRB 140610A: Swift detection of a burst
- Konus-Wind observation of GRB 140606B
- GRB 140606B: Swift XRT refined analysis
- GRB 140521A: AAO optical upper limit
- GRB 140606A: AAO optical upper limit
- GRB 140607A: Swift-BAT refined analysis
- IPN Triangulation of GRB 140606B
- GRB 140606B: Swift/UVOT Upper Limits
- GRB140606B/iPTF14bfu: Discovery Channel Telescope Optical Detection
- GRB 140606B: Swift XRT position
- GRB 140606B / Fermi 432717114 / iPTF 14bfu: Keck redshift
- GRB 140607A: Swift detection of a burst
- GRB 140606B: Fermi GBM detection
- Fermi 423717114: Additional P48 and P60 observations